Userland: Move command-line utilities to Userland/Utilities/

Userland/Utilities/cat.cpp

@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/Vector.h>
+#include <LibCore/ArgsParser.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+int main(int argc, char** argv)
+{
+    if (pledge("stdio rpath", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    Vector<const char*> paths;
+
+    Core::ArgsParser args_parser;
+    args_parser.set_general_help("Concatenate files or pipes to stdout.");
+    args_parser.add_positional_argument(paths, "File path", "path", Core::ArgsParser::Required::No);
+    args_parser.parse(argc, argv);
+
+    Vector<int> fds;
+    if (!paths.is_empty()) {
+        for (const char* path : paths) {
+            int fd;
+            if (StringView { path } == "-") {
+                fd = 0;
+            } else if ((fd = open(path, O_RDONLY)) == -1) {
+                fprintf(stderr, "Failed to open %s: %s\n", path, strerror(errno));
+                continue;
+            }
+            fds.append(fd);
+        }
+    } else {
+        fds.append(0);
+    }
+
+    if (pledge("stdio", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    for (auto& fd : fds) {
+        for (;;) {
+            char buf[32768];
+            ssize_t nread = read(fd, buf, sizeof(buf));
+            if (nread == 0)
+                break;
+            if (nread < 0) {
+                perror("read");
+                return 2;
+            }
+            size_t already_written = 0;
+            while (already_written < (size_t)nread) {
+                ssize_t nwritten = write(1, buf + already_written, nread - already_written);
+                if (nwritten < 0) {
+                    perror("write");
+                    return 3;
+                }
+                already_written += nwritten;
+            }
+        }
+        close(fd);
+    }
+
+    return 0;
+}